of the International Union of Geodesy and Geophysics · - Integration and validation of local geoid estimates 2.3 Satellite Gravity Missions - GRACE Follow-On (GRACE FO) mission started

International Association of Geodesyof the International Union of Geodesy and Geophysics

Challenges to be faced by Geodesy in the coming years from the perspective of the

International Association of Geodesy (IAG)

Hermann Drewes IAG Secretary General

SIRGAS Symposium, Aguascalientes, Mexico, 8-12 October 2018

Retos para ser afrontados por la geodesia en los años que vienen desde la perspectiva de la

Asociación Internacional de Geodesia (IAG)

Organisation of International Science

International Science Council (ISC) (2018: merger of ICSU and ISSC)

Sciences: IAU, ICA, IGA, … Social SciencesIUGG

International Union of Geodesy and Geophysics (IUGG)

IAMASIACS IAGA IAHS IAGIAPSO IASPEI IAVCEI

International Association of Geodesy (IAG): 71 Member countries

Council: Representatives of the member countries

Executive Committee: 16 members (elected by the Council)

Bureau: Administrative work

Office: Management (Secretary General)

2H. Drewes: Challenges to be faced by IAG – SIRGAS Symposium, Aguascalientes, Mexico, 8-12 October 2018

Mission and objectives of the IAG

The mission of the IAG is the advancement of geodesy by- furthering geodetic theory through research and teaching,- collecting, analysing, modelling and interpreting observational data,- by stimulating technological development and - providing a consistent representation of the figure, rotation, and

gravity field of the Earth and planets, and their temporal variations.


The objectives of the IAG are to achieve the mission by studying all geodetic problems related to Earth observation and global change, i.e.:- Definition, establishment, and maintenance of global and regional

reference systems for interdisciplinary use;- Gravity field of the Earth;- Rotation and dynamics of the Earth and planets;- Positioning and deformation;- Ocean, ice and sea level.- Atmosphere and hydrosphere.

IAG Scientific Structure 2015 – 2019

President: Harald Schuh, GermanyVice-president: Zuheir Altamimi, FranceSecretary General: Hermann Drewes, Germany

Bureau

General:Gravim.:Geom.: BGI

IDEMS PSMSLISG

IGFS

Scientific Services

IGETSILRS IVSIDS

IERS BIPMIGS ICGEM

(Representatives in the EC: R. Neilan, US, R. Barzaghi, IT, A. Nothnagel, DE)

Global Geodetic Observing System (GGOS) (R. Gross, US)

(EC Members at Large: Y. Dang, CN, M. C. Pacino, AR; Past President: Ch. Rizos, AU)

Commissions

4 Applications(M. Santos, CA)

1 Reference Frames(G. Blewitt, US)

3 Geodynamics(M. Hashimoto, JP)

Inter-Commission Committee on Theory (P. Novák, CZ)

2 Gravity Field(R. Pail, DE)

Communication and Outreach Branch (COB) (J. Ádám, HU)


Commission 1 “Reference Frames” Activities

1.1 Coordination of Space Techniques- Co-location using clocks and new sensors: New site ties concepts- Performance simulations and architectural trade-off (of the ITRF)

WG1: Site survey and co-location

WG2: Modelling environmental loading effects

WG3: Troposphere ties

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1.2 Global Reference Frames- IERS Conventions: post-seismic model must be clarified

1.3 Regional Reference Frames- EUREF, SIRGAS, NAREF, AFREF, APREF, Antarctica- Time-dependent transformations between reference frames

1.4 Interaction of Celestial and Terrestrial Reference Frames- Consistent realization of ITRF, ICRF and EOP: new ICRF3 (only AGU)

H. Drewes: Challenges to be faced by IAG – SIRGAS Symposium, Aguascalientes, Mexico, 8-12 October 2018

Challenges of geodesy to reference frames


SLR, GNSS, VLBIaltimetry, gravity filed missions, …

Referencesystems,

sat. orbits

Solid Earth deformation, sea level rise, changes in hydro-/atmosphere

Observations Applications

Point positions,sea surface, Earth rotation, gravity

Parameters

Nearly all observations are done via satellites. The orbits are derived from observations at stations of the reference frame. Errors in the station coordinates enter into the orbits.

Problems to be solved:• Time evolution of the reference frame:

velocities or frequent epoch frames?• Scale of the observation techniques; • Realisation of the geocentric origin;• Realisation of a non-rotating frame.

1 ppb = 6.4 mm in h

Commission 2 “Gravity Field” Activities

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2.1 Gravimetry and Gravity Network- Absolute and superconducting gravity measurements

WG: Relativistic Geodesy: Towards a New Geodetic Technique

2.2 Methodology for Geoid and Physical Height Systems- Integration and validation of local geoid estimates

2.3 Satellite Gravity Missions- GRACE Follow-On (GRACE FO) mission started on May 22, 2018

2.6 Gravity and Mass Transport in the Earth System

2.4 Regional Geoid Determination- Europe, South, N & Central America, Africa, Asia-Pacific, Antarctica

2.5 Satellite Altimetry- New International Altimetry Service under discussion


Challenges of geodesy to gravity field models

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- Establishment of the International Gravity Reference Frame (IGRF);- Support regional gravity field determinations;- Release a conventional global gravity field model (GGM).


Differences of potential values WP of EGM2008 (Pavlis et al. 2008) and EIGEN6C4 (Förste et al. 2014), both n=2190.Discrepancies up to ±20 cm (maximum differences, particularly in South America come up to ± 2 m) (Sánchez 2018)

Commission 3 “Earth Rotation and Geodynamics”

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3.1 Earth Tides and Geodynamics- New International Geodynamics and Earth Tide Service (IGETS)

JSG1 : Intercomparison of Gravity and Height ChangesJWG1: Theory of Earth Rotation and ValidationJWG2: Constraining Vertical Land Motion of Tide Gauges

3.2 Crustal Deformation- SC3.2 dissolved; new SC3.2 Volcano Geodesy (joint with IAVCEI)

3.3 Earth Rotation and Geophysical Fluids- Global mass transport, Earth rotation and low-degree gravity change

3.4 Cryospheric Deformations- Glacial Isostatic Adjustment (GIA) research

3.5 Tectonics and Earthquake Geodesy- Joint Sub-commission planned with IASPEI


Challenges of geodesy to rotation & geodynamics

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- Prove consistency of the ICRF3 (released by IAU 2018) with ITRF;

- Effects of mass displacements (atmosphere, hydrosphere and solid Earth on Earth rotation;


- For geodynamics research, establish joint (Sub-)commissions with• IAHS (hydrosphere)• IAPSO (oceans)• IASPEI (seismology, approved and under construction)• IAVCEI (volcanology, approved and under construction)

Commission 4 “Positioning and Applications”

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4.1 Emerging positioning technologies and GNSS augmentation- Multi-sensor systems - Indoor positioning and navigation- 3D point cloud monitoring - Robust positioning for urban trafic

WG1: Biases in multi-GNSS data processingWG2: Integer ambiguity resolution for multi-GNSS PPP and PPP-RTK

4.2 Geo-spatial mapping and geodetic engineering- Mobile mapping technologies - Geodesy in mining engineering- Mobile health monitoring - Building information modelling

4.3 Atmosphere remote sensing- Iono-atmosphere coupling - Real-time iono-/atmosph. monitoring- Multi-dimens. Ionosphere - Impact on GNSS-positioning- Ionosphere scintillations - Troposphere tomography

4.4 Multi-constellation GNSS- Integrity monitoring for PPP


Challenges of geodesy to positioning & applications

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- Real-time multi-sensor positioning in engineering; - Improve ionosphere models (scintillations, multi-dimensional);- Study troposphere-ionosphere coupling;- Develop troposphere topography.


Inter-Commission Committee on Theory

10: High-rate GNSS11: Multi-resolution aspects of potential field theory12: Methods for recovery of high-resolution gravity field models13: Integral equations of potential theory for continuation and

transformation of classical and new gravitational observables14: Fusion of multi-technique satellite geodetic data15: Regional geoid/quasi-geoid modelling for sub-centimetre occur.16: Earth’s inner structure from geodetic and geophysical sources17: Multi-GNSS theory and algorithms18: High resolution harmonic analysis & synthesis of potential fields19: Time series analysis in geodesy20: Space weather and ionosphere21: Geophysical modelling of time variations in deformation & gravity22: Definition of next generation terrestrial reference frames

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Joint Study Groups with Commissions / Services


IAG Services on Geometry

IERS: International Earth Rotation and Reference Systems’ Service

IVS: International Service for Geodesy and Astrometry

ILRS: International Laser Ranging Service

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IGS: International GNSS Service

IDS: International DORIS

All the techniques’ Services compute epoch station coordinates (weekly, monthly, session-wise) and provide them as free or loosely constrained networks to the ITRF processing centres of the IERS.


IAG Services on Gravimetry

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IGFS: International Gravity Field Service

IGETS: International Geodynamics and Earth Tide Service

IDEMS: International Digital Elevation Model Service

ICGEM: International Centre for Global Earth Models

BGI: Bureau Gravimetrique International

ISG: International Service for the Geoid


COST-G: Combination Service for Time-variable Gravity field sol’s

Comprehensive Services

16

BIPM: Bureau International des Poids et Mesures- Time Department -

PSMSL: Permanent Service of Mean Sea Level

- Sea level at tide gauges

All the Services have a general structure including- Central Bureau coordinating all internal affairs,- Analysis Centres generating the Services‘ products.

All the Services are working on a voluntary basis, unpaid by IAG or other international organisations.

The Services are cooperating in the Global Geodetic Observing System (GGOS) to achieve consistency of products.


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GGOS Structure

GGOS Consortium(Steering and Election Committee)

GGOS Science Panel

GGOS Bureau of Networks & Observations

• IAG Service Network Representatives (1)

• Committee on Satellite Missions

• Committee on Data and Information Systems

• Committee on Performance Simulations and

Architectural Trade-Offs

GGOS Bureau of Products & Standards

• IAG Service Analysis Coordinators & Representatives (1)

• Committee on Earth System Modeling

• Working Group on ITRS Standards for ISO TC 211

• Working Group on the Establishment of the Global

Geodetic Reference Frame (GGRF)

GGOS Coordinating Board(Decision-Making Body)

GGOS Executive Committee(Management Board)

GGOS Coordinating Office

• Director

• Secretariat

• Outreach and User Linkage

• Web and Social Media

• Focus Area Coordination

Manager of External Relations

GGOS Focus Areas

• Unified Height System

• Geohazards

• Sea Level Change, Variability, and Forecasting

• Geodetic Space Weather MonitoringIERS Working GroupSite Survey and Co-location

Reporting Direction

Reporting Reporting

IERS Conventions CentreStandards and Conventions

External

Stakeholders


GGOS Affiliates

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Challenges of geodesy to GGOS


- Develop a strategy to design, integrate and maintain the fundamental geodetic network of co-located instruments;

- Define the essential geodetic variables and provide fundamental geodetic parameters;

- Establish the International Height Reference Frame (IHRF) according to IAG Resolution 2, 2015;

- Improve the global interaction with GGOS by establishing regional and national alliances.

IHRF status April 2018 (Sánchez, L., 2018)

SIRGAS Symposium, Mendoza, Argentina, 27-29 November 2017

Cooperation with External Organisations

United Nations (UN)• 2012: Initiative on the Global Geospatial Information Management (UN-GGIM)

• 2015: UN Resolution on the Global Geodetic Reference Frame (GGRF) approved

• 2015 – 2016: A Roadmap for the GGRF was developed

• 2016: At the UN-GGIM sixth session in New York on August 5, 2016, the UN

Committee of Experts on the GGIM

- endorsed the GGRF Roadmap and

• 2017: Decision to establish a permanent Sub-Committee on Geodesy.

• UN-GGIM Working Group on the GGRF: 32 Member States and 2 organisations:

- International Association of Geodesy (IAG),

- World Health Organisation (WHO)

• UN-GGIM Geospatial Societies (previously Joint Board of Geo-Information

Societies (JBGIS) with GSDI, IAG, ICA, IEEE-GRSS, FIG, IGU, INIA, ISPRS)

• UN Office of Outer Space Affairs (UN-OOSA): Representatives to

- Space-based Information for Disaster Management and Emergency Response (SPIDER)

- International Committee on Global Navigation Satellite Systems (ICG)


Cooperation with External Organisations

COSPAR (ICSU Committee on Space Research)• COSPAR Sub-commission B2: International Coordination of Space Techniques

for Geodesy and Geodynamics (CSTG) is identical with IAG Commission 1

Group on Earth Observation (GEO)• IAG represented by its GGOS (Global Geodetic Observing System) is a Participating

Organisation of GEO

International Organisation for Standardisation (ISO) • TC211 Geographic Information / Geomatics (2 representatives)

• Control Body for Geodetic Registry Network (2 representatives)

International Astronomical Union (IAU)• Commission A2: Rotation of the Earth (representative)

• Joint Services and Working Groups:

- International Earth Rotation and Reference Systems Service (IERS)

- International VLBI Service for Geodesy and Astrometry (IVS)

International Hydrographic Organisation (IHO)• Advisory Board on the Law of the Sea (ABLOS) (4 representatives)


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IAG Publications

Publications

• Journal of Geodesy (monthly issues edited by Springer)

• IAG Symposia Series (latest volumes)- Vol. 147 International Symposium on Earth and

Environmental Sciences for Future Generations (2018)- Vol. 148 International Symposium on Gravity, Geoid and

Height Systems (2018)- Vol. 149 Joint IAG/IASPEI Scientific Assembly

Kobe, Japan, 2017 (2019)


• Geodesist’s Handbook 2016(https://link.springer.com/article/10.1007/s00190-016-0948-z)- IAG history, statutes, bylaws, rules, membership- Report of the General Assembly 2015- Structure and program descriptions 2015-2019- General information

https://link.springer.com/article/10.1007/s00190-016-0948-z

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IAG Reports, Position Papers, Outreach

IAG Reports

• IAG Report 2015-2017 (Travaux de l’AIG Vol. 40)

https://iag.dgfi.tum.de/en/iag-publications-position-papers/ iag-reports-2017-online/- Activity reports of all IAG components and sub-components

• Annual and quadrennial reports (ibid.)

• Monthly Newsletters(http://www.iag-aig.org/index.php?tpl=cat&id_c=44)

Position Paper on the UN Global Geodetic Reference Frame (GGRF)

Communication and Outreach Branch (COB)

• IAG Outreach Homepage (https://www.iag-aig.org)

• IAG Office Homepage (https://iag.dgfi.tum.de)


https://iag.dgfi.tum.de/en/iag-publications-position-papers/iag-reports-2017-online/

http://www.iag-aig.org/index.php?tpl=cat&id_c=44

http://www.iag-aig.org/

https://iag.dgfi.tum.de/

IAG/IUGG General AssemblyMontreal, Canada, July 8 - 19, 2019

6 IAG Symposia G01 Reference systems and frames;G02 Static gravity field and height systems;G03 Time variable gravity field;G04 Earth rotation and geodynamics;G05 Multi-signal positioning, remote sensing and applications;G06 Monitoring and understanding the dynamic Earth with

geodetic observations.

8 Joint Symposia with other associations (led by IAG)

20 Joint Symposia with other associations (sponsored by IAG)(led by IACS, IAGA, IAHS, IAMAS, IAPSO, IASPEI, IAVCEI)

9 Union Symposia (co-organized by IAG)(led by IUGG or IUGG Commissions)


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Most provoking challenges

• Reference Frames - Co- and post-seismic deformation models• Gravity field - International Gravity Reference Frame (IGRF)• Rotation & Geodyn. - Joint commissions with other associations• Pos. & Applications - Atmosphere (iono- & troposphere) models• Geodetic theory - Relativistic geodesy, new geodetic techniques• GGOS - International Height Reference Frame (IHRS)

- Essential geodetic variables- New GRS to replace GRS80

• Geometry Services - Reliable continuous ITRF• Gravity Services - Recommended global gravity field model• Combining Services - Adopt IAG resolutions (W0)

- Sea level variation model


Conclusions

Invitation to IAG Membership via IUGG

IUGG member countries from the Americas (1 unit = US$ 1975)Regular members Associate membersArgentina Brazil BoliviaCanada Chile PeruColombia Costa RicaMexico NicaraguaUSA

Invitation to SIRGAS countries and others to become membersCuba was member till 1996 Belize JamaicaDominican Rep. was member till 1971 Ecuador PanamaGuatemala was member till 2000 El Salvador ParaguayHaiti was member till 1971 Guyana SurinameUruguay was member till 2000 Honduras Trinidad & TobagoVenezuela 2008


To join IUGG including IAG visit www.iugg.org/join/index.php)

All geodesists are invited to become an individual member (https://www.iag-aig.org or https://iag.dgfi.tum.de). It is free of charge for all (undergraduate … PhD) students!

Thank you for your attention!¡Gracias por su atención!

Invitation to IAG Membership via IUGG

https://www.iag-aig.org/

https://iag.dgfi.tum.de/

Documents

of the International Union of Geodesy and Geophysics · - Integration and validation of local geoid estimates 2.3 Satellite Gravity Missions - GRACE Follow-On (GRACE FO) mission started